Strain sensing film, pressure sensor and hybrid strain sensing system

ABSTRACT

The present application provides a strain sensing film, a pressure sensor, and a hybrid strain sensing system. The strain sensing film includes a semiconductor thin-film, at least two resistors are disposed on the semiconductor thin-film, one resistor has a different response to a strain with respect to at least another resistor, thereby enhancing resistance to external environmental disturbances and improving the accuracy of pressure measurements.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Appl. filed under 35 USC 371 ofInternational Patent Application No. PCT/CN2021/075913 with aninternational filing date of Feb. 8, 2021, which is based upon andclaims the benefit of U.S. Provisional Application Ser. No. 62/992,000filed on Mar. 19, 2020, and U.S. Provisional Application Ser. No.63/064,086 filed on Aug. 11, 2020. The contents of which areincorporated herein by reference.

FIELD

The present application relates to the field of semiconductor thin-filmtechnology, and in particular, to a strain sensing film, a pressuresensor, and a hybrid strain sensing system.

BACKGROUND

At present, pressure sensors include such as resistor strain gauge type,capacitance induction type, and piezoelectric ceramic type. These typesof pressure sensors are all formed by complex circuit design andstructural design to form the pressure sensor itself. For example, forthe resistor strain gauge type, it is necessary to select strain gaugesthat meet requirements of resistors and deviations from manywell-produced strain gauges, meanwhile, the strain gauges are combinedto form a certain circuit structure, the colloid is used to connect asensing structure, and the deformation of the strain gauge underpressure is low, so the sensing structure needs to be preciselypositioned and carefully bonded. The capacitance induction type needs tostrictly control a distance between each capacitive point and a panel,pressure information is obtained through a changing of the distance, soan extremely high accuracy on processing and assembly for themanufacturing process is required. For the piezoelectric ceramic type,the pressure is acquired based on a short-term voltage variationobtained by instantaneous impact on the piezoelectric ceramic. Theproduction of this type of pressure sensors requires a uniform andconsistent piezoelectric ceramic piece, and needs to be installed on aparticular structure through a special installation method.

However, the manufacturing process of existing pressure sensors has theproblem of high practical cost, which brings difficulties to thelarge-scale promotion of pressure sensing. In particular, these pressuresensors have low resistance to external environmental disturbances.Under external conditions such as temperature variations, the pressuresensors will be affected, resulting in inaccurate pressure measurement.

SUMMARY

An objective of the embodiments of the present application is intendedto, but not limited to, improve the sensitivity and accuracy of pressuremeasurement during production and use, and enhance resistance toexternal environmental disturbances, by providing a strain sensing film,a pressure sensor, and a hybrid strain sensing system.

To solve the above problem, solutions provided by the embodiments of thepresent application are as follows.

In accordance with a first aspect of the present application, a strainsensing film is provided, which includes: a semiconductor thin-film, atleast two resistors are disposed on the semiconductor thin-film, oneresistor has a different response to a strain with respect to at leastanother resistor.

In one embodiment, the semiconductor thin-film includes at least one ofa silicon (Si) thin-film, a germanium (Ge) thin-film, a gallium arsenide(GaAs) thin-film, and a gallium nitride (GaN) thin-film, a siliconcarbide (SiC) thin-film, a zinc sulfide (ZnS) thin-film, or a zinc oxide(ZnO) thin-film.

In one embodiment, the one resistor has a different gauge factor withrespect to the at least another resistor.

In one embodiment, the one resistor is arranged in a differentorientation with respect to the at least another resistor.

In one embodiment, the one resistor is oriented in a directionperpendicular to the at least another resistor.

In one embodiment, a Wheatstone bridge is arranged on the semiconductorthin-film, and the Wheatstone bridge includes a first resistor, a secondresistor, a third resistor, and a fourth resistor. The second resistorand the third resistor have positive gauge factors, and the firstresistor and the fourth resistor have negative gauge factors.

In one embodiment, dR2/R2=GF2×∈, dR1/R1=GF1×∈, a voltage signal of theWheatstone bridge dU=Vcc/2×(dR2/R2−dR1/R1)=Vcc×GF1×∈, where GF2 is apressure-inductance coefficient of a second resistor, GF1 is apressure-inductance coefficient of a first resistor, GF1=−GF2, ∈ is astrain at the Wheatstone bridge, and Vcc is a voltage supplied to theWheatstone bridge.

In one embodiment, a temperature sensor is provided in the semiconductorthin-film.

In one embodiment, the strain sensing film is also provided with asignal processing circuit. The signal processing circuit is configuredto receive a temperature detection signal output by the temperaturesensor, and determine a sensor correction sensitivity according to apreset correlation table of the effective gauge factor versustemperature.

In one embodiment, the thickness of the semiconductor thin-film is lessthan or equal to 70 μm.

In one embodiment, the thickness of the semiconductor thin-film is lessthan or equal to 50 μm.

In one embodiment, the thickness of the semiconductor thin-film is lessthan or equal to 30 μm.

In one embodiment, the thickness of the semiconductor thin-film is lessthan or equal to 25 μm.

In one embodiment, the thickness of the semiconductor thin-film is lessthan or equal to 20 μm.

In one embodiment, the thickness of the semiconductor thin-film is lessthan or equal to 15 μm.

In accordance with a second aspect of the present application, apressure sensor is provided. The pressure sensor includes a substrate,and at least one side surface of the substrate is provided with thestrain sensing film according to any one of the above.

In accordance with a third aspect of the present application, a hybridstrain sensing system is provided. The hybrid strain sensing systemincludes: a substrate; a signal processing circuit; and the strainsensing film according to any one of the above. The strain sensing filmis attached to the substrate, and the strain sensing film is inconnection with the signal processing circuit.

Embodiments of the present application provide a strain sensing film, apressure sensor, and a hybrid strain sensing system. The strain sensingfilm includes a semiconductor thin-film, and at least two resistors aredisposed on the semiconductor thin-film, one resistor and at leastanother resistor respond differently to a strain, thereby enhancingresistance to external environmental disturbances and improving theaccuracy of pressure measurements.

BRIEF DESCRIPTION OF DRAWINGS

In order to explain the solutions in embodiments of the presentapplication more clearly, the following will briefly introduce thedrawings that need to be used in the description of the embodiments orthe existing technologies. Obviously, the drawings in the followingdescription are merely some embodiments of the present application, andfor persons skilled in the art other drawings may also be obtained onthe basis of these drawings without creative labor.

FIG. 1 shows an exemplary strain sensing film deposited on a substrateto form a variable resistor in accordance with an embodiment of thepresent application;

FIG. 2 shows an exemplary strain sensing film deposited on a substrateto which a force is applied, in accordance with an embodiment of thepresent application;

FIG. 3 shows an exemplary Wheatstone bridge, in which one arm R1 of thebridge is replaced by a piezoresistive resistor, and R2, R3, R4 arereference resistors, in accordance with an embodiment of the presentapplication;

FIG. 4 shows eight exemplary illustrative arrangements of resistors on astrain sensing film for one embodiment of the present application;

FIG. 5 is a schematic diagram of a strain sensing film in accordancewith an embodiment of the present application; and

FIG. 6 is a schematic diagram of a pressure sensor in accordance with anembodiment of the present application.

DETAILED DESCRIPTION

In order to make the objectives, solutions and beneficial effects of thepresent application more comprehensible, the present application will bedescribed in further detail below with reference to the drawings andembodiments. It should be understood that specific embodiments describedherein are intended only to interpret the present application, and arenot intended to limit the present application.

It should be noted that when a component is referred to as being “fixedto” or “disposed on” another component, it can be directly or indirectlyon the other component. When an element is referred to as being“connected to” another element, it can be directly or indirectlyconnected to the other element. The orientation or positionalrelationship indicated by terms “upper”, “lower”, “left”, “right”, etc.is based on the orientation or positional relationship shown in thedrawings, and is used only for the convenience of description, ratherthan indicating or implying the device or element referred to must havea specific orientation, be constructed and operated in a specificorientation, and thus cannot be construed as a limitation to the presentapplication, for those of ordinary skill in the art the specificmeanings of the above terms can be understood according to specificsituations. The terms “first” and “second” are only used for the purposeof description, and should not be understood as indicating or implyingrelative importance or implicitly indicating the number of features. Thephrase “a/the plurality of” means two or more, unless expresslyspecified otherwise.

The temperature coefficient of resistance (TCR) represents a relativevariation of resistance value when the temperature varies by 1° C., andthe unit is ppm/° C. (i.e., 10⁻⁶/° C.). The gauge factor (GF) of theresistance strain gauge represents a relative variation of the straingauge resistance caused by a unit strain of the resistance strain gauge,where dR/R=GF×∈, dR/R is a resistance-variation rate, and c is amechanical strain of the material. An effective gauge factor (GF_eff) isa ratio of an actual resistance variation to an ideal strain assumingthat the semiconductor thin-film has no effect on the structuralstrength. For a specific structure, a deformation of the structure isdetermined when a certain external force is applied, while when asemiconductor thin-film having a large elastic modulus such as silicon(Si) is attached to the structure, the deformation of Si is generallysmaller than the deformation of the carrier structure. As the thicknessof the film increases, the strain deformation at the film becomessmaller, and corresponding the resistance variation decreases, that is,the effective GF decreases with the increase of the thickness of thefilm.

In accordance with an embodiment of the present application, a strainsensing film is provided, which includes a semiconductor thin-film, andon the semiconductor thin-film, at least two resistors are disposed, oneresistor and at least another resistor have different responses to astrain.

In this embodiment, the at least two resistors on the semiconductorthin-film have different responses to a strain may be achieved byarranging two resistors to have different thicknesses, differentplacement positions, different preparation materials, and differentresistor shapes.

Further, one resistor has a different gauge factor with respect to theat least another resistor.

Since the gauge factor of one resistor is different from that of the atleast another resistor on the semiconductor thin-film, at least twodifferent electrical signals are generated in two resistors, or at leasttwo resistance values are simultaneously generated, during astrain-sensing process. Thereby the sensitivity of the semiconductorthin-film is increased, and thus an accurate strain signal can bedetected even in small-strain circumstances.

In one of the embodiments, at least two resistors are arranged indifferent orientations, or at least two resistors are made of differentpiezoresistive materials, or at least two resistors have differentthicknesses, so that the gauge factor of one resistor is different fromthat of the at least another resistor on the semiconductor thin-film.

The main types of strain sensors are based on piezoresistive straingauges or their variants. In case that piezoresistive materials are usedin the strain gauges, the conductivity or resistivity varies when thematerial is under stress. In one common form of such strain gauges, athin-film of piezoresistive material is deposited or attached or bondedto a substrate to form a variable resistor. FIG. 1 shows an exemplarystrain sensing film deposited on a substrate to form a variableresistor, where the deposition manner may be gluing, mechanicalfixation, surface mount (SMT), and so on. After the variable resistor isformed on the substrate, electrical contact is made to measure theresistance value R_(G0). For the purpose of demonstration, FIG. 1 showstwo mechanical supports 101. It should be understood that other designof the support structure may also be used as long as the structure canpredictably and repeatably translate the applied force into localizedstrain. FIG. 2 shows an exemplary strain sensing film 20 deposited onthe substrate 10 when a force is applied to the substrate, and theresistance value in the structure now becomes R_(G1), as shown in FIG. 2, any deformation of the substrate will cause a variation in resistancevalue of a variable resistor R1, and the strain or force can becalculated based on a measurement of the variation in resistance value(for example, the variation in resistance value is measured through theWheatstone bridge structure shown in FIG. 3 ). The deformation of thesubstrate may also be measured using a half bridge, as shown in FIG. 3 ,where R1 is the variable resistor.

Referring to FIG. 4 , the strain sensing film is a semiconductorthin-film 201 having a (100) crystallographic orientation, and at leasttwo resistors 202 are disposed on the semiconductor tin film 201, oneresistor and at least another resistor are arranged in differentorientations.

In one of the embodiments, the semiconductor thin-film 201 includes atleast one of a silicon (Si) thin-film, a germanium (Ge) thin-film, agallium arsenide (GaAs) thin-film, a gallium nitride (GaN) thin-film, asilicon carbide (SiC) thin-film, a zinc sulfide (ZnS) thin-film, or azinc oxide (ZnO) thin-film.

In one of the embodiments, one resistor is oriented in a directionperpendicular to the at least another resistor.

For p-type doped (100) crystalline silicon materials, the gauge factorsat two mutually perpendicular orientations are basically the same inmagnitude and opposite in sign, while the TCR has little correlationwith orientations. Thus, the signal quantity output by the strainsensing film under the same deformation can be enhanced, by arrangingtwo mutually perpendicular resistors on the same semiconductorthin-film, and the influence of the ambient temperature on the signalquantity can be reduced.

Referring to FIG. 4, 201 represents the semiconductor thin-film on whichthe resistors are disposed, (that is not drawn to scale of the actualsemiconductor thin-film). 202 represents the resistor deposited on thesemiconductor thin-film. The rectangular shape of the resistor shown inFIG. 4 does not represent the actual shape of the resistor, but is usedto indicate the direction of current flow, the current flows parallel tothe long sides of the rectangle. Actual resistors may contain differentaspect ratios, the actual resistors may even be a combination ofmultiple sections, each section has its own aspect ratio. Again, thelocation of each resistor is illustrative and may not be their actuallocation, as is the case for all configurations in FIG. 4 . FIG. 4A toFIG. 4H only show the orientation relationship of the resistors, nottheir positions.

In FIG. 4A, four resistors are disposed on the semiconductor thin-film201, and each resistor is perpendicular to the other two resistors.

FIG. 4B may represent the same configuration of FIG. 4A, as FIG. 4A andFIG. 4B both include four resistors, each resistor is perpendicular tothe other two resistors, and each resistor is parallel to at least oneside of the semiconductor thin-film 201.

In FIG. 4C, four resistors are disposed on the semiconductor thin-film201, each resistor is perpendicular to the other two resistors, and eachresistor is arranged at an angle of 45 degrees with respect to at leastone side of the semiconductor thin-film 201.

In FIG. 4D, four resistors are disposed on the semiconductor thin-film201, and the four resistors are arranged in parallel with each other.

In one embodiment, the four resistors in FIG. 4D are arranged inparallel.

In FIG. 4E, two resistors are disposed on the semiconductor thin-film201, and the two resistors are arranged perpendicular to each other.

In FIG. 4F, two resistors are disposed on the semiconductor thin-film201, and the two resistors are arranged in parallel with each other.

In one embodiment, the two resistors in FIG. 4F are arranged inparallel.

In FIG. 4G, three resistors are disposed on the semiconductor thin-film201, and an angle formed between two adjacent resistors is 45 degrees.

In FIG. 4H, three resistors are disposed on the semiconductor thin-film201, and an angle formed between two adjacent resistors is 60 degrees,or 120 degrees.

In this embodiment, one resistor is arranged in a different orientationwith respect to at least another resistor, due to the anisotropy of thesemiconductor material, the gauge factors in the two orientations aredifferent, and thus at least two different electrical signals aregenerated in two resistors, or at least two resistance values aresimultaneously generated, during the strain-sensing process. To bespecific, in the embodiments of the present application, the“orientation” of the resistor refers to the direction of the currentflowing through the resistor, rather than the geometric shape of theresistor.

Referring to FIG. 4 , the semiconductor thin-film 201 may include tworesistors forming a half-Wheatstone bridge, and the gauge factor of oneresistor may be different from the gauge factor of the other resistor.

In one embodiment, the semiconductor thin-film 201 may include tworesistors forming a half-Wheatstone bridge, and a strain level of oneresistor in a sensing device may be different from the strain level ofthe other resistor in the strain sensing device.

In one embodiment, the direction of current flow in at least oneresistor is perpendicular to the direction of current flow in at leastanother resistor.

In this embodiment, the semiconductor thin-film 201 may include tworesistors forming a half-Wheatstone bridge, and among the two resistorsforming the half-Wheatstone bridge, the direction of current flow in oneresistor may be perpendicular to the direction of current flow in theother resistor.

In one embodiment, the direction of current flow in at least oneresistor is perpendicular to the direction of current flow in at leastanother resistor.

In one embodiment, the Wheatstone bridge is provided on thesemiconductor thin-film, and the Wheatstone bridge includes a firstresistor, a second resistor, a third resistor and a fourth resistor. Thesecond and third resistors have positive gauge factors, and the firstand fourth resistors have negative gauge factors.

In this embodiment, as shown in FIG. 5 , the strain sensing film is asemiconductor thin-film 201 having a (100) crystallographic orientation.On semiconductor thin-film 201, a first resistor R1, a second resistorR2, a third resistor R3, and a fourth resistor R4 are arranged. For thep-type doped (100) crystalline silicon material, the gauge factors attwo mutually perpendicular orientations are basically the same in sizeand opposite in sign, while the TCR has little correlation withorientations. Thus, by arranging the second resistor R2 and the firstresistor R1 to be perpendicular to each other, and arranging the thirdresistor R3 and the fourth resistor R4 to be perpendicular to eachother, two resistors have positive gauge factors, and two resistors havenegative gauge factors are arranged on one semiconductor thin-film,thereby the signal quantity output from the Wheatstone bridge under thesame deformation can be enhanced, and the influence of the ambienttemperature on the signal quantity can be reduced.

In one embodiment, dR2/R2=GF2×∈, dR1/R1=GF1×∈, the voltage signal ofWheatstone bridge dU=Vcc/2×(dR2/R2−dR1/R1)=Vcc×dR2/R2, GF2 is apressure-inductance coefficient of the second resistor R2, GF1 is apressure-inductance coefficient of the first resistor R1, GF1=−GF2,where ∈ is the strain at the Wheatstone bridge, and Vcc is a voltagesupplied to the Wheatstone bridge.

In this embodiment, four resistors are arranged on the semiconductorthin-film 201, and the signal quantity output from the Wheatstone bridgeunder the same deformation can be significantly enhanced by adjustingthe angles of the four resistors. For example, the second and thirdresistors are arranged to have positive gauge factors, the first andfourth resistors are arranged to have negative gauge factors, at thistime, under the same deformation, dR2/R2=−dR1/R1, the voltage signal ofthe Wheatstone bridge dU=Vcc/2×(dR2/R2−dR1/R1)=Vcc×dR2/R2.

In one embodiment, the semiconductor thin-film 201 is provided with atemperature sensor.

In this embodiment, the temperature variation in a deformation regioncan be accurately measured through the temperature sensor built in thesemiconductor thin-film 201, so that the resistance variation caused bythe temperature variation in the deformation region can be compensatedmore accurate, thereby avoiding measurement error caused by the externaltemperature sensor being unable to measure the exact temperature of thesemiconductor thin-film 201.

In one of the embodiments, the semiconductor thin-film 201 is alsoprovided with a signal processing circuit, and the signal processingcircuit is configured to receive a temperature detection signal outputby the temperature sensor, and determine a sensor correction sensitivityaccording to a preset correlation table of the effective gauge factorversus the temperature.

In this embodiment, the signal processing circuit may be integrated inthe semiconductor thin-film, and the signal processing circuit is inconnection with the Wheatstone bridge and the temperature sensor, andthe temperature value detected by the temperature sensor is applied to apreset sensitivity calibration algorithm to correct the temperatureeffect of the strain sensing film, the sensitivity calibration algorithmmay be derived based on theoretical calculations or data measured undercontrolled conditions, or based on theoretical calculations and datameasured under controlled conditions.

In one of the embodiments, a plurality of temperature sensors are builtin the semiconductor thin-film 201, and the signal processing circuitmay acquire the temperature of the sensors by performing weightedcalculation on a plurality of temperature detection signals output bythe plurality of temperature sensors, and then y acquire thecorresponding effective gauge factor based on the temperature of thesensors obtained through the weighted calculation.

In one embodiment, the semiconductor thin-film 201 is provided with aplurality of resistors, the plurality of resistors are configured toform a Wheatstone bridge or a half-Wheatstone bridge, and the pluralityof resistors are arranged adjacently.

In this embodiment, the plurality of resistors in the Wheatstone bridgeor the half Wheatstone bridge are adjacent to each other and insulatedfrom each other. In specific applications, a consistent variation intemperature among the plurality of resistors of the Wheatstone bridgewhen the temperature varies can be realized due to the good thermalconductivity of semiconductor thin-film 201, and thus errors in pressuredetection caused by temperature differences among the resistors on thesame semiconductor thin-film 201 can be avoided.

Further, the temperature detection signal is output by the temperaturesensor through a temperature contact electrode, and the signalprocessing circuit may be provided outside the semiconductor thin-film201. The signal processing circuit can correct the temperature effect ofthe strain sensing film based on the temperature detection signal outputby the temperature sensor built in the semiconductor thin-film 201, forexample, the temperature value detected by the temperature sensor isapplied by the signal processing circuit to the preset sensitivitycalibration algorithm to obtain the effective gauge factor. Thesensitivity calibration algorithm may be derived based on theoreticalcalculations or data measured under controlled conditions, or based on acombination of the theoretical calculations and data measured undercontrolled conditions.

In one embodiment, the signal processing circuit may also include avoltage source, a current source, an amplifier circuit, ananalog-to-digital converter (ADC), a digital-to-analog converter (DAC),a multiplexer (MUX), a micro-controller (MCU) or any other common signalprocessing and control circuit.

In a specific application, the strain sensing film may operate in a DCmode, and may also operate in an AC mode or a pulsed mode. The strainsensing film may also operate in a low-power sleep mode. The strainsensing films may witch to a high-power detection mode when an externaltrigger event occurs, and switch back to the low-power mode after thetrigger event is passed.

In one embodiment, a bridge contact electrode connected to theWheatstone bridge or the half Wheatstone bridge is provided on thesemiconductor thin-film 201, and configured for outputting a bridgevoltage signal.

In one embodiment, the temperature sensor may be connected to the signalprocessing circuit through a contact electrode, or the temperaturesensor may be connected to an external control unit through the contactelectrode. The external control unit may be an external signalprocessing circuit.

In one of the embodiments, the temperature contact electrode may includea conductive contact formed by common printing techniques such as screenprinting, inkjet printing, roll-to-roll printing, etc. The conductivecontact may also be thermally annealed to form the Ohmic contactelectrode, and the conductive contact may also be formed by wire bondingor soldering processes.

In one of the embodiments, the bridge contact electrode may include aconductive contact formed by common printing techniques such as screenprinting, inkjet printing, roll-to-roll printing, etc. The conductivecontact may also be thermally annealed to form the Ohmic contactelectrode, and the conductive contact may also be prepared by theprocess of wire bonding.

In one of the embodiments, the temperature contact electrode may also beformed by solder ball and flip-chip processes.

In one of the embodiments, the bridge contact electrode may also beformed by solder ball and flip-chip processes.

In a specific application, the effective gauge factor of thesemiconductor thin-film varies with the temperature, the higher thetemperature, the smaller the effective gauge factor. When thetemperature detection signal output by the built-in temperature sensoris used for the calibration of the strain sensing film, the correlationtable of the effective gauge factor versus temperature can be obtainedthrough preset calibration tests, then the corresponding effective gaugefactor can be obtained through the temperature value corresponding tothe temperature detection signal output by the temperature sensor, andthen based on the calibrated effective gauge factor, the pressure valuedetected by the strain sensing film is determined.

In one embodiment, the thickness of the semiconductor thin-film 201 isless than or equal to 70 μm.

In one embodiment, the thickness of the semiconductor thin-film 201 isless than or equal to 50 μm.

In one embodiment, the thickness of the semiconductor thin-film 201 isless than or equal to 30 μm.

In one embodiment, the thickness of the semiconductor thin-film 201 isless than or equal to 25 μm.

In one embodiment, the thickness of the semiconductor thin-film 201 isless than or equal to 20 μm.

In one embodiment, the thickness of the semiconductor thin-film 201 isless than or equal to 15 μm.

In this embodiment, the elastic modulus of the silicon material isequivalent to the elastic modulus of steel, which is about 160 GPa. Thelarger the thickness, the more difficult the deformation. Thus, thethickness of the silicon wafer may be reduced to be less than or equalto 70 um, or to be less than or equal to 50 um, or to be less than orequal to 30 um, to be less than or equal to 25 um, or to be less than orequal to 20 um, or to be less than or equal to 15 um, at this time, thesemiconductor thin-film will become soft and easily deformed, whichimproves the efficiency of strain transfer from the substrate to thesemiconductor thin-film, thereby improving the effective gauge factor ofthe semiconductor thin-film, and significantly increasing the signalquantity.

In accordance with an embodiment of the present application, it is alsoprovided a strain sensing film, which includes a semiconductorthin-film, and on the semiconductor thin-film, at least two resistorsare disposed, one resistor and at least another resistor have differentstrain levels in a strained state.

In this embodiment, the gauge factor (GF) of the resistance strain gaugerepresents the relative variation of the strain gauge resistance causedby the unit strain of the resistance strain gauge, where dR/R=GF×∈, dR/Ris the resistance-variation rate, ∈ is the mechanical strain of thematerial. As the strain level of one resistor on the semiconductorthin-film is provided have a strain level different from that of atleast another resistor in the strained state, the dR/R of at least tworesistors on the semiconductor thin-film are different, At this time,when the semiconductor thin-film is in the strained state, the tworesistors respond differently to the strain, and thus two differentelectrical signals are generated, or at least two resistance values aregenerated simultaneously, thereby increasing the sensitivity of thesemiconductor thin-film, and thus an accurate strain signal can bedetected even in small-strain circumstances.

In one of the embodiments, one resistor is arranged in a region having adifferent strain level with respect to at least another resistor.

In accordance with an embodiment of the present application, it is alsoprovided a pressure sensor. The pressure sensor includes a substrate,and at least one side surface of the substrate is provided with thestrain sensing film according to any one of the above embodiments.

In this embodiment, the substrate may include a common substrate usedfor circuits such as printed circuit boards, flexible printed circuit(FPC) boards, and may include a common substrate used in printableelectronics, such as a polyamide Imine (PI) sheet, a polyethyleneterephthalate (PET) sheet, a polyurethane (PU) sheet, a polycarbonate(PC) sheet, an epoxy sheet, or may also include a glass fiberboard(FR-4), a glass sheet, a metal sheet, a paper, a composite sheet, a woodsheet, a ceramic sheet, etc.

In a specific application, as shown in FIG. 6 , the strain sensing films5 are arranged on two sides of the substrate 4. Reference sign 3represents a deformation neutral surface of the substrate, and thesubstrate 4 is pasted on the panel 1 by the double-sided tape 2. Themodulus of the double-sided tape is much smaller than that of the panel1, and the panel 1 may be made of metal, glass, plastic, ceramic, wood,or the like. By pressing, the panel 1 is deformed, and the sensor moduleis driven to deform by the double-sided tape. The deformation neutralsurface 3 of the pressure sensor module is at the middle position of thesensor as shown in FIG. 6 . The deformation values on the upper andlower sides of the module are the same in value and opposite in sign.The strain sensing films are arranged on the upper and lower sides,compared with the strain sensing film arranged on one side, twice thesignal can be generated, and thus the signal-to-noise ratio is improved.

In accordance with an embodiment of the present application, it is alsoprovided a hybrid strain sensing system. The hybrid strain sensingsystem includes: a substrate; a signal processing circuit; and thestrain sensing film according to any one of the above embodiments. Thestrain sensing film is attached to the substrate, and is in connectionwith the signal processing circuit.

In this embodiment, the strain sensing film is in connection with thesignal processing circuit, the strain sensing film is attached to thesubstrate, or at least one strain sensing film and one signal processingcircuit are arranged on the substrate, thereby forming a hybrid strainsensing system to provide high sensitivity and flexibility for variousapplication scenarios.

In one of the embodiments, the mode of attaching may be gluing,mechanical fixing, surface mounting (SMT) and so on.

Fields of application of such strain sensing systems include but are notlimited to strain sensing, or force sensing, or touch sensing or tactilesensing of smartphones, in any human-machine interface ormachine-machine interaction, such as tablet computers, personalcomputers, touch screens, virtual reality (VR) systems, gaming systems,consumer electronics, vehicles, scientific instruments, toys, remotecontrols, industrial machinery, biomedical sensors to monitor heartrate, blood pressure, and movement and acceleration of skin, muscles,bones, joints and other body parts; robotic sensors for measuring touch,local pressure, local tension, motion and acceleration of any part ofthe robot; vibration sensors for buildings, bridges and any otherman-made structures; sensors to monitor strain, pressure, motion,acceleration of any part of a vehicle that may be used on land, air,water or space; motion, acceleration, and strain sensors that can beintegrated into smart fabrics; and any other application that requiresthe measurement of local static or dynamic deformation, displacement orstrain.

Embodiments of the present application provide a strain sensing film, apressure sensor, and a hybrid strain sensing system. The strain sensingfilm includes a semiconductor thin-film, and the semiconductor thin-filmis provided with at least two resistors, one resistor has a differentresponse to a strain with respect to at least another resistor, therebyenhancing resistance to external environmental disturbances andimproving the accuracy of pressure measurement.

The forgoing are only optional embodiments of the present application,and are not intended to limit the present application. For those skilledin the art, various modifications and variations of this application arepossible. Any modification, equivalent replacement, improvement, and thelike, made within the fundamental designs and the principle of thepresent application, should all be included in the protection scope ofthe present application.

1. A strain sensing film, comprising: a semiconductor thin-film; whereinat least two resistors are disposed on the semiconductor thin-film, oneresistor has a different response to a strain with respect to at leastanother resistor.
 2. The strain sensing film according to claim 1,wherein the semiconductor thin-film comprises at least one of a silicon(Si) thin-film, a germanium (Ge) thin-film, a gallium arsenide (GaAs)thin-film, and a gallium nitride (GaN) thin-film, a silicon carbide(SiC) thin-film, a zinc sulfide (ZnS) thin-film, or a zinc oxide (ZnO)thin-film.
 3. The strain sensing film of claim 1, wherein the oneresistor and the at least another resistor have different gauge factors.4. The strain sensing film of claim 1, wherein the one resistor and theat least another resistor are arranged in different orientations.
 5. Thestrain sensing film of claim 1, wherein the one resistor is oriented ina direction perpendicular to the at least another resistor.
 6. Thestrain sensing film of claim 1, wherein a Wheatstone bridge is arrangedon the semiconductor thin-film, and the Wheatstone bridge comprises afirst resistor, a second resistor, a third resistor, and a fourthresistor, wherein the second resistor and the third resistor havepositive gauge factors, and the first resistor and the fourth resistorhave negative gauge factors.
 7. The strain sensing film of claim 6,wherein dR2/R2=GF2×∈, dR1/R1=GF1×∈, a voltage signal of the Wheatstonebridge dU=Vcc/2×(dR2/R2−dR1/R1)=Vcc×dR2/R2, wherein GF2 is apressure-inductance coefficient of a second resistor, GF1 is apressure-inductance coefficient of a first resistor, GF1=−GF2, ∈ is astrain at the Wheatstone bridge, and Vcc is a voltage supplied to theWheatstone bridge.
 8. The strain sensing film of claim 1, wherein atemperature sensor is provided in the semiconductor thin-film.
 9. Thestrain sensing film of claim 8, wherein a signal processing circuit isfurther provided in the strain sensing film, and the signal processingcircuit is configured to receive a temperature detection signal outputby the temperature sensor, and determine a sensor correction sensitivityaccording to a preset correlation table of an effective gauge factorversus temperature.
 10. The strain sensing film of claim 1, wherein thesemiconductor thin-film has a thickness being less than or equal to 70μm.
 11. The strain sensing film of claim 1, wherein the semiconductorthin-film has a thickness being less than or equal to 50 μm.
 12. Thestrain sensing film of claim 1, wherein the semiconductor thin-film hasa thickness being less than or equal to 30 μm.
 13. The strain sensingfilm of claim 1, wherein the semiconductor thin-film has a thicknessbeing less than or equal to 25 μm.
 14. The strain sensing film of claim1, wherein the semiconductor thin-film has a thickness being less thanor equal to 20 μm.
 15. The strain sensing film of claim 1, wherein thesemiconductor thin-film has a thickness being less than or equal to 15μm.
 16. The strain sensing film of claim 1, wherein the one resistor hasa different strain level with respect to the at least another resistorin a strained state.
 17. The strain sensing film of claim 16, whereinthe one resistor is arranged in a region having a different strain levelwith respect to the at least another resistor.
 18. A pressure sensor,comprising: a substrate, wherein at least one side surface of thesubstrate is provided with the strain sensing film according to claim 1.19. A hybrid strain sensing system, wherein the hybrid strain sensingsystem comprises: a substrate; a signal processing circuit; and thestrain sensing film according to claim 1, wherein the strain sensingfilm is attached to the substrate, and the strain sensing film is inconnection with the signal processing circuit.